Nitrogen Management in CA systems in Malawi (Plant)


Conservation agriculture (CA) is being widely promoted to smallholder farmers by many organizations in Malawi. CA is a set of three principles: 1) minimum soil disturbance (often no-till), 2) year round soil cover (residue retention, mulching, or cover cropping), and 3) crop diversification (crop rotations or intercropping). The goal of this project is to develop CA systems that can improve crop production on smallholder farmers in Malawi.

The specific objectives of this study are to evaluate maize and cowpea response to different soil management and N fertilizer rates on both research stations and on smallholder farms. We analyzed the effects of 4 different N fertilizer rates (0 kg N/ha, 30 kg N/ha, 60 kg N/ha, and 90 kg N/ha) on:

  1. Conventional tillage: ridge and furrow tillage, all residues were cleared from the field prior to planting, and there is no crop rotation.

  2. No-till continuous maize: maize is planted into the previous season's residue and there is no crop rotation.

  3. No-till maize - cowpea intercropping: maize and cowpea are intercropped and planted into the previous season's residue and there is no crop rotation.

  4. No-till maize - cowpea rotation (maize phase): maize is planted into the cowpea residue from the previous season.

  5. No-till maize - cowpea (cowpea phase): Cowpea is planted into the maize residue from the previous season.


Chlorophyll Fluorescence Phi2

Using an orange measuring light (pin 15) and red saturating and actinic light (pin 20), this performs the standard PAM fluorescence measurement but includes a background constant actinic light which is equivalent to the ambient PAR value.

Chlorophyll content (SPAD) I

REQUIREMENTS: Firmware v0.38 or lower (used for older devices which do not have a SPAD calibration, generally device ID 87 and lower).Measures transmission at 940nm and 650nm in order to determine the 'greenness' of a leaf, an indicator of chlorophyll content and nitrogen content. The 940 is used to account for leaf thickness.


  1. District (Multiple Choice)
  2. Crop (Multiple Choice)
  3. Treatment (Multiple Choice)
  4. Fertilizer rate (Multiple Choice)
  5. Block (Multiple Choice)
  6. Year (Short Answer)
  7. Weeks after planting (Multiple Choice)


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